Pregnant women often experience a heightened sense in cravings they had prior to their pregnancy. Expectant mothers who smoke before becoming pregnant may face the difficult challenge to stave off tobacco cravings. According to a recent study, pregnant smokers who engage in 20 minutes of exercise can significantly decrease tobacco cravings.

Based on the Pregnancy Risk Assessment and Monitoring System (PRAMS) latest data, among women who smoked three months before their pregnancy, 54 percent quit during pregnancy and 44 percent relapsed within six months after giving birth.

Smoking while pregnant can lead to a series of detrimental health outcomes that affect the placenta – the source of the baby’s food and oxygen. Tobacco use may also lower the amount of oxygen that is available for the expectant mother and the infant increasing their heart rate. The Centers for Disease Control and Prevention says children of mothers who smoked during pregnancy are at greater risk for being born prematurely, low birth weight, respiratory problems, and stillbirth among many others.

Publishing in the journal Addictive Behaviors, researchers sought to examine the effects of 20 minutes of exercise on tobacco cravings and tobacco withdrawal symptoms among temporarily, inactive pregnant smokers. 30 pregnant women in their second trimester in Canada and England who smoked more than five cigarettes a day and were not regular exercisers were a part of the study. Before the start of the experiment the women were told to not smoke for 15 to 19 hours.

Half of the participants were randomized into two groups: one group was told to walk on a treadmill while the second group was told to watch a home gardening video for 20 minutes every day. The researchers assessed cravings and tobacco withdrawal symptoms immediately before the activity, during at 10 minutes, immediately post, and at 10, 20, and 30 minutes post-condition.

The findings revealed 20 minutes of exercise was associated with a reduction in cravings along with tobacco withdrawal symptoms. The exercising women were found to be less irritable, restless, tension and other symptoms associated with smoking. The walkers had an average 30 percent reduction in the desire to smoke based on a seven-point scale the researchers used in the study. After thirty minutes of exercising, the same group of women reported a 17 percent craving reduction.

"This translates not as a cure for quitting, but it can be part of a strategy," said Dr. Sharon Phelan, a fellow with the American Congress of Obstetricians and Gynecologists (ACOG) and professor at the University of New Mexico School of Medicine in Albuquerque to Reuters Health. "The challenge is that there isn't one reason why pregnant women have an addiction.”

The results of this study could only be applied to women 25-years-old – the average age in the study. However, Harry Prapavessis, lead author of the study and director of the Exercise and Health Psychology Laboratory at Western University in Ontario, Canada believes they can repeat the findings with older or young pregnant smokers. The challenge they face is recruiting pregnant women who smoke because of the social stigma associated with smoking while pregnant.

The researchers hope to see the craving effect be reproduced when women go for a brisk walk for 15 to 20 minutes in their natural setting.

The American College of Obstetrics and Gynecology recommends pregnant women to do the same amount of cardio exercise as non-pregnant women by staying active for 30 minutes a day. Regular exercise not only helps you stay in shape while sporting a baby bump, it can also improve your ability to cope with labor.

For expert safety tips on how to work out while pregnant, click here.